Primary objective is to measure the effect of use of combined oral contraceptive (COC) or depomedoxyprogesterone acetate (DMPA) on the acquisition of HIV infection. Secondary objectives are to: determinme if HIV seroconversion rates are modified by the presence or duration of other sexually transmitted diseases differently in users of COCs, DMPA, or no hormones, and examine the effect orf COCs or DMPA on factors which have been shown to influence HIV transmission, such as bacterial vaginosis, herpes simplex or human papillomavirus infection, genital HIV shedding, and viral fitness of non-clade B HIV. This study was established through intraagency agreement in FY 1997; the sole source contract for continuation of this study by NICHD was negotiated in Fy2000, to continue through FY2004.